Mycotoxins (from the Greek word μúκηζ (mykes, mukos) “fungus”) are toxins produced by an organism of the Fungi Kingdom, including mushrooms, molds and yeasts. They develop in agricultural products, and especially in species of fruit and cereal grains. Even though their harmful effects have been acknowledged for centuries, only in the last three decades has society become fully aware of exactly what they represent for the economy and health.
When the conditions are favorable, fungi proliferate, forming colonies and at specific levels of moisture, temperature or oxygen in the air, mycotoxin levels can become high. Mycotoxins are compounds greatly differing in their chemical, biological and toxicological properties, therefore their danger greatly varies. While some fungi produce harsh toxins, others are deadly, cause identifiable diseases or health problems, weaken the immune system without producing specific systems or act as allergenics or irritants. There are also mycotoxins which have no known effect on the human organism.
Furthermore mycotoxins are ubiquitous compounds, which means that the problem of mycotoxicosis begins in the field and continues during the entire transformation-marketing chain, reaching the consumer. The consumption of feeds prepared with ingredients such as corn, barley, wheat, oats and rye, oilseed, peanut seed, cotton seed or palm seed cakes contaminated with mycotoxins causes both mycotoxicosis in animals, and problems of mycotoxin residues in derivative products, such as milk, meat and eggs. Therefore, the contamination of cereals and any product susceptible of comprising mycotoxins due to fungi causes not only enormous losses after the harvest, but it is also a source of toxic and harmful substances for humans.
Lastly, mycotoxins resist decomposition, so they remain in the food chain in meats and dairy products. Even temperature treatments, such as cooking and freezing, do not destroy all the mycotoxins.
Therefore, many mycotoxins have a harmful effect for health, first of all on animals fed with cereals that could be infected, but also, second of all, on people through the food chain. In fact, cases of acute diseases in humans, such as aflatoxin-induced hepatitis, vascular and enteric ergotism and mycotoxicosis due to trichothecenes have been reported in different continents. Circumstantial data also link chronic diseases, such as liver and stomach cancer, to the consumption of foods contaminated by aflatoxin and deoxynivalenol.
Additionally, the economic consequences of mycotoxins in terms of food and feed losses, reduction of animal productivity, loss of foreign revenue earnings, increase of the cost of inspection and analyses, injury compensation claims, costs of prevention and control measures are considerable.
Based on the foregoing, there is a need to find prevention and control measures which would ensure that the mycotoxins present in feeds do not reach anyone consuming the contaminated material, thus preventing them from exerting their effect.
The publication “Prevention of toxic effects of mycotoxins by means of nonnutritive adsorbent compounds” by Ramos et al. (1996) describes that the mycotoxins from aflatoxin group become fixed, in accordance with their specific molecular structure, with a high specificity in some mineral adsorbents such as zeolite, bentonite, and other aluminosilicates and other minerals (see the publication A. J. Ramos, Journal of Food Protection, volume 59(6), 1996, pp. 631-641). This publication corroborates what had already been disclosed in German patent application DE3810004, relating to the use of bentonite for adsorption of mycotoxins in humans or animals, or in U.S. Pat. No. 5,149,549, relating to the use of a clay, montmorillonite, for adsorption of mycotoxins in contaminated foods, or also in European patent application EP1890804, relating to the use of stevensite for adsorbing mycotoxins.
However, adsorption of mycotoxins on non-modified minerals is not efficient for the majority of other mycotoxins.
Other methods which were developed trying to also extend the adsorption capacity of mineral adsorbents to other important mycotoxins (non-aflatoxins), such as, for example, zearalenone, ochratoxins, fumonisins, T2-toxin, deoxynivalenol or vomitoxin, mycotoxin HT-2, or nivalenol, are described below.
Document U.S. Pat. No. 6,165,485 relates to a bentonite-based clay modified with a quaternary amine comprising in its structure a benzol substituent, and which can furthermore be treated with iodine to improve its efficacy as a biocide.
More specifically, in the field of animal feeds, document U.S. Pat. No. 6,045,834 proposes the combination of modified yeast cells and of inorganic minerals such as zeolite, bentonite or aluminum silicate to deactivate mycotoxins present in feeds and, thus, preventing the absorption of the mycotoxins in the animal blood.
In document U.S. Pat. No. 5,639,492, an acid-activated calcium bentonite clay is used to adsorb mycotoxins in feeds.
Document YU P-838/00 describes the use of a clinoptilotite/heulandite-type mineral organically modified with a quaternary amine having a long-chain aliphatic group for adsorbing aflatoxin and non-aflatoxin mycotoxins comprised in animal feeds. The main object in this document underlies a controlled correction of the surface of the mineral, and more specifically of the hydrophilic or hydrophobic nature of the mineral by means of the addition of a controlled amount of a quaternary amine having a long-chain aliphatic group with preferably 18 carbon atoms. The amount of amine added is adapted in accordance with the type of mycotoxins to be adsorbed.
Finally, European patent EP1150767B1, the equivalent of which in Spain is patent ES2201820, should be pointed out. This document relates to a mycotoxin adsorbent, especially for the adsorption of aflatoxins and other mycotoxins (non aflatoxins) in feeds by means of the mixture of a non-modified montmorillonite-type silicate (especially bentonite), and a montmorillonite-type silicate (especially bentonite, or vermiculite) organically modified with quaternary ammonium compounds with at least one C10 to C22 alkyl group and at least one aromatic substituent. It discloses that, by means of the modification of a layered silicate with a relatively small amount of a quaternary ammonium compound with a long-chain C10 to C22 alkyl group and at least one aromatic substituent, a significant increase in the performance of the adsorption of aflatoxin and non-aflatoxin mycotoxins can be achieved. It also discloses that acid-activated bentonites can be used.
However, it should be pointed out that the drawback of this type of mineral adsorbent such as zeolite, bentonite, aluminum silicates . . . is that they are usually included at concentrations of 1-2% by weight, which reduces the nutritional value of the food. Furthermore, given that their activity is not too much specific, in addition to adsorbing only a narrow range of mycotoxins, they can present selectivity problems leading to an unwanted adsorption of nutrients such as vitamins, minerals and amino acids. As a consequence, there is certain concern due to the fact that the use of some aluminosilicates in feed could adsorb nutrients or micronutrients in the gastrointestinal tract (Turkish Journal of Veterinary and Animal Sciences, 2008, 32(3), 183-189).
For example, riboflavin (E101), also known as vitamin B2, is a micronutrient which plays a key role in maintaining good health in humans and animals. One of its functions consists of eliminating harmful substances from the organism, in addition to participating in the metabolism of other vitamins. It has been demonstrated that a high adsorption for this vitamin exits in the interlayer spaces of smectite (Clays and Clay Minerals, Vol. 31, No. 6, 435-439, 1983). This adverse nutritional effect is also described in publication Animal Research, 51, 2002, 81-99, since the large amounts to be added in order to achieve a noticeable effect reduce the bioavailability of certain vitamins or minerals in the diet.
It is therefore very important to find new products which, on the one hand, have efficient properties in the adsorption of a broad spectrum of mycotoxins, without, on the other hand, limiting the bioavailability of nutrients and micronutrients in animals.
Based on the foregoing and, furthermore, knowing that the contamination of feeds due to mycotoxins represents a very serious problem since it has such a very important impact on the economy and on health, it is necessary to continue investigating to obtain an efficient and specific adsorption of mycotoxins present in feeds which is easy to put into practice.
The object of the present invention is to provide an alternative mycotoxin adsorbent, suitable for feeds, which effectively adsorbs any type of mycotoxin in a selective manner to prevent the unwanted interaction with nutrients, and which, furthermore, has a simplified process of preparation in order to be easily carried out into practice, and with a low economic cost.